Abstract
ABSTRACTAre there common mechanisms of neurogenesis used throughout an entire nervous system? Making use of the well-defined and relatively small size of the nervous system of the nematodeC. elegans, we explored to what extent canonical proneural class I/II bHLH complexes are responsible for neurogenesis throughout the entireC. elegansnervous system. Distinct, lineage-specific proneural “class II” bHLH factors are generally thought to operate via interaction with a common, “class I” bHLH subunit, encoded by Daugtherless in flies, the E (E2A, E2-2, HEB) proteins in vertebrates, andhlh-2inC. elegans. To eliminate function of all proneuronal class I/II bHLH complexes, we therefore genetically removed maternal and zygotichlh-2gene activity. We observed broad effects on neurogenesis, but still detected normal neurogenesis in many distinct neuron-producing lineages of the central and peripheral nervous system. Moreover, we find thathlh-2selectively affects some aspects of neuron differentiation while leaving others unaffected. While our studies confirm the function of proneuronal class I/II bHLH complexes in many different lineages throughout a nervous system, we conclude that their function is not universal, but rather restricted by lineage, cell type and components of differentiation programs affected.
Publisher
Cold Spring Harbor Laboratory